Means for determining the quantity of liquid in refrigerating apparatus.



No. 744.121. PATENTED NOV. 1'7, 1903. J. SMAILL. MEANS FOR DETERMININGTHE QUANTITY OF LIQUID IN REFRIGERATING APPARATUS.

APPLIOATION FILED APR 22, 1903.

N0 MODEL.

Tn: noams PETERS cov PNUTO-LITHU WASHINGTON. u c.

UNITED STATES Patented November 17, 1903.

PATENT OFFICE.

JOHN SMAILL, OF PORT OHALMERS, NEW ZEALAND.

MEANS FOR DETERMINING THE QUANTITY OF LIQUID IN REFRIGERATING APPARATUS.

SPECIFICATION forming part of Letters Patent N0./74=4,121, datedNovember 17, 1903.

Application filed April 22, 1903.

To all whom, it may concern:

Be it known that I, JOHN SMAILL, refrigerating engineer,of PortChalmers, New Zealand, have invented a certain new and useful ImprovedMeans for Determining the Quantity of Liquid in Refrigerating Apparatus,of which the following is a specification.

In the working of the ammonia system of freezing one of the mostimportant things is to know exactly how much ammonia is con tained inthe system. A large header or reservoir is usually supplied with allplants of whatever make, and to know what quantity of liquid ammonia iscontained in this reservoir gages are fitted with glass tubes, so thatthe level. of the ammonia is readily seen. The objection, which ispractically prohibitive, is that should the glass break there will be agreat loss of ammonia, if not a total loss. Automatic valves aresometimes fitted; but these, owing to corrosion, grit, and other causesdue to infrequent use, fail to act when required.

This invention provides a ready means of finding the exact quantity ofliquid in the reservoir.

It consists of an apparatus for reducing below freezing-point thetemperature of the liquefied agent used for freezing purposes. Theliquid so cooled will show a clear frostline externally on the device,indicating exactly the level of the liquid contained therein and in thereservoir. I

The invention consists, preferably, of a vertical column having pipeconnections at top and bottomwith the reservoir. The top pipeconnection, however, may be dispensed with. Inside the column is fittedan expansion-pipe, controlled by a regulating-valve. A connection isprovided to supply the expansion-pipe through the regulating-valve withliquid from the liquid contained in the column. The return end of theexpansion-pipe is connected to the suction side of the refrigeratingapparatus.

The action of the invention is as follows: The column containing theliquid surrounding the expansion-pipe willbecome externally Serial No.153,868. (No model.)

frosted at the level of the contained liquid, owing to the fact thatthis liquid transmits cold from the expansion-pipe many times fasterthan the gas in the column does.

The accompanying drawing is a sectional view of the invention withconnections to reservoir and part end view of reservoir.

A vertical gage-column 1 is connected by a lower branch pipe 2 with thebottom ofa liquid-reservoir 3 and by an upper branch pipe 4 with the topof the liquid-reservoir. An expansion-pipe 5 is fixed within thegagecolumn, and one end of it is connected by means of a passage 6 tothe inside of the column. The liquid in the reservoir attains the samelevel in the column, and the supply of this liquid to the expansion-pipeis controlled by a regulator 7. A branch pipe 8, leading from the returnend of the expansion-pipe, connects with the suction side of the system.The liquid expanding in the expansion-pipe cools the liquid and gas inthe column, and the cooling is transmitted more rapidly to the exteriorof the column through the liquid contained in it than through the gascontained in it. There results a frost-line 9 on the exterior of thecolumn, below which frost appears. This line goes up and down inaccordance with the level of the liquid in the column which correspondsto the level of the liquid in the reservoir. Hence the level of thisliquid can be ascertained by inspection, and consequently the quantityof same in the reservoir. By an obvious adaptation the frost-line may beshown on the outside of the reservoir.

Having now described my inventiolnwhat I claim as new, and desire tosecure by Letters Patent, is

1. Means for determining the quantity of liquid in refrigeratingapparatus consisting of a reservoir, a vertical column, pipe connectionsbetween the reservoir and the column and means in the column for causinga line of frost on the outside of the column of the same extent as theliquid in the reservoir, substantially as described.

2. Means for determining the quantity of liquid in refrigeratingapparatus consisting of a vertical column, pipe connections between thebottom of said Vertical column and a reservoir, an expansion-pipe withinsaid 5 vertical column, a passage between said vertical column and saidexpansion-pipe, a regulating-valve in said passage, and a branch pipebetween said expansion-pipe and the refrigerating system, substantiallyas described. 10

In witness whereof I have hereunto set my hand in presence of twowitnesses.

JOHN SMAILL.

Witnesses:

A. J. PARK, J. R. PARK.

